Back in the late 1970's into the early 1980's Chris Claremont and John Byrne put together a sequence of issues of the X-Men that was something special at the time and it remains so to this very day.
The culmination of this three year period was The Dark Phoenix Saga. They'd taken the huge decision to turn plain old Jean Gray into the Phoenix, one of the most powerful characters in the history of comics. Alas, such power was proving to be too much for her and we come to the story of Dark Phoenix.
I don't want to give anything away here, but it's safe to say that these issues manage the nigh-on impossible feat of telling a huge story while still making us care for the individuals concerned. Claremont and Byrne's resolution to the storyline was an extra-ordinarily brave decision. Unquestionably a high water mark for comics. (Marvel's later decision to undo this ending in an attempt to make some big money was one of the scuzziest things I've ever read in comics, but Claremont and Byrne weren't to know this at the time.)
John Byrne's art was at its best in these issues. He's clearly trying his best to imitate Neal Adams, who was so hugely influential on comic book art. In later days he developed his own style, and quite right too, but in truth it never looked this good again. His pencils are beautifully inked by Terry Austin.
These issues regularly turn up in comic book readers all time top ten. It's amongst my favourites too. As there's nothing anywhere near this good out there these days, I expect it always will be.
Very highly recommended.